Solenoids have many different applications as actuators or drivers. For example, solenoids can be used to open valves, to drive dot matrix print heads, etc. For many applications, the solenoid must respond very quickly to the current which energizes the coil.
One application for a solenoid is opening a valve of the type which includes a ball and a valve seat with the ball being urged against the valve seat by fluid pressure and/or a spring. For valves of this type, the ball needs to be displaced only very slightly in order to open the valve; however, rapid opening of the valve, and hence a fast response time of the solenoid, are essential.
Because the displacement of the ball to open the valve is very short and because the stroke of the solenoid is correspondingly short, it is difficult to accurately locate the solenoid with respect to the ball so that the short stroke of the solenoid can properly open and close the valve. Of course, the stroke of the solenoid could be increased, and this would reduce the importance of accurately locating the solenoid with respect to the ball. However, to the extent that the stroke is increased, the response time of the solenoid is decreased.
With the prior art, the solenoid is mounted on the valve housing by threads or other suitable means, and the spacing between the solenoid and the valve housing is established by shims. The installation of shims requires substantial assembly time and makes adjustment of solenoid location relative to the valve housing more difficult.